Introduction
In humans, renal transporters play an important role in drug disposition and drug-drug interactions. Currently available cell-based experimental models often fail to predict renal transporter activity and are not scalable to a predictive clinical outcome due to in vitro-in vivo discrepancy. To overcome the challenges, we successfully developed a human Proximal Tubule Kidney-Chip model for assessment of renal transporter-based drug-drug interactions. Here we present efflux activities using probe substrates including digoxin mediated by P-gp, tetraethylammonium and metformin mediated collaboratively by OCT1/2, MATE1, and MATE2-K, and para-aminohippuric acid mediated by OAT1/3.